Valid Strobes; Table 6.7 Data Buses Used And Valid Strobes - Renesas H8S/2437 Hardware Manual

6.5.2

Valid Strobes

Table 6.7 shows the data buses used and valid strobes for each access space.
In a read, the RD signal is valid for both the upper and lower halves of the data bus. In a write, the
HWR signal is valid for the upper half of the data bus, and the LWR signal for the lower half.
Table 6.7 Data Buses Used and Valid Strobes
Access
Area Size
8-bit access Byte
space
16-bit access Byte
space
Word
Note: Undefined:
Invalid: Input state with the input value ignored.
Ports or others:
Rev. 1.00, 09/03, page 104 of 704
Read/
Write Address
Read —
Write —
Read Even
Odd
Write Even
Odd
Read —
Write —
Undefined data is output.
Input/output pins for ports or on-chip peripheral devices cannot be used
as data buses.
Upper Data Bus
Valid (D15 to D8/AD15
Strobe to AD8)
RD
Valid
HWR
RD
Valid
Invalid
HWR
Valid
LWR
Undefined
RD
Valid
HWR, LWR
Valid
Lower Data Bus
(D7 to D0/AD7 to
AD0)
Ports or others
Ports or others
Invalid
Valid
Undefined
Valid
Valid
Valid